Prof. H. James-Clark on the American Spongilla. 71 



VI. — The American Spongilla a Craspedofe Flagellate Infii- 

 sorian. By H. James-Clark, A.B., B.S., Prof. Nat. 

 Hist. Kentucky University, Lexington, Ky.* 



[Plate XI.] 



The argument of Hackel and others, that the Sponges are 

 essentially compound Polypi, is virtually based upon the as- 

 sumption that the minor (afferent) and major (efferent) ostioles 

 of the former correspond to the mouths of the latter, and that 

 the profusely branching afferent and efferent canals of the 

 Sponges are strictly comparable with similar canals in the 

 polypidom of Halcyonarians — and, by implication, that the 

 cilia-bearing cells of the interior lining wall of the zoophyte 

 find their homologues in the ciliated cell-like bodies of the in- 

 terior chambers of the Porifera. If, now, it should turn out 

 that these last are not altogether mere cell-components of a 

 tissue, but are each, severally, an independent body, although 

 closely connected with others in a common bond, then the 

 attempted parallelism between the two groups must utterly 

 fail of confirmation. The tendency of Carter's later investi- 

 gations, and our own too, is to show that this is no vain 

 supposition. 



For ourselves, we hold that each ciliated body of the sponge 

 is a cephalic member (a cephalid in this case) of a polycephalic 

 individual f- We believe, as far as we can understand his un- 

 decided, rather hesitating position, Carter's latest decision is 

 that the sponge is a community of amoebous individuals J, 

 and not a polycephalic unit. Yet, whichever view prevails, the 

 tendency is the same, and the polyp theory is negatived most 

 unquestionably. The incompatibility of the interior organisms 

 of the two groups above mentioned is so great that it would 

 seem as idle to elaborate a proof of it as to attempt the demon- 

 stration of an axiom. The question is really circumscribed, 

 according to the method of Hackel, to arguing that, since a 

 system of branching canals in the sponge reminds one very 

 strongly of the intricate network of passage-ways in the basal 

 parts of certain polyps, therefore the two are homologous and 

 bear an identical relation to the rest of the organism. Carter 

 has answered this far-fetched homology with considerable de- 

 tail in a recent paper (" On new Sponges," &c., Ann. & Mag. 



* From Silliman's American Journal, December 1871. 



t See our article on "Polarity and Polycephalism," Sill. Am. Jouru., 

 January 1870. 



\ See Carter, " On Fecimdation in the two Vohoces ; on Eiidoriva, 

 Spongilla" &c., Ann. & Mag. Nat. Hist., January 1859, also for July 

 1871, "On new Sponges," &c. 



